Grating



Nov. 22, 1960 H. NAGIN 2,960,918

GRATING Filed Sept. 27, 1956 2 Sheets-Sheet 1 INVENToga. Barol nagm Nov.22, 1960 H. NAGIN 2,960,918

v GRATING Filed sept. 27, 195s 2 sheets-sheet 2 INVENTOIL Barcl Basin BYf MVM QWM United States Patenti@ "i GRATING Haroid Nagin, Pittsburgh,Pa., assignor to Reliance Steel Products Company, McKeesport, Pa., acorporation of Pennsylvania Filed Sept. 27, 1956, Ser. No. 612,487

6 Claims. (Cl 94-30) This invention is for a new composite grating suchas those used in bridge iloors and other tratc bearing sursurfaces. aswell as platforms, sidewalks and elsewhere.

Grating members of the type referred to generally have longitudinallyextending bearer bars or main load carrying members, and another set oftransversely extending bars, called cross bars. The cross bars areusually welded or otherwise secured to the bearer bars with the tops ofthe two sets of bars lying in the same plane, thereby forming areticulate grating.

In my copending application Serial No. 456,380, led September 16, 1954,now Patent No. 2,895,389, I have shown a grating designed to provide animproved traction surface by having a relatively thin coating ofabrasive grains secured over the tread surface by an expoxy resin. Sucha mixture will adhere rmly to the metal, even under heavy trafficconditions.

In rny copendng application Serial No. 471,666, filed November 29, 1954,a grating is provided in which one or both sets of bars has the top edgeof each bar provided with a trough-like formation into which a fillingof resin and abrasive mixture is placed, the filling being heaped to alevel above the tops of the troughs.

The present invention has for its principal objects the provision of animproved and unique grating, and more especially, composite gratingformed of metal with antiskid trfic bearing composition applied thereto.A further object is to provide a grating having desirable propertieswhen used either for light traiiic, such as sidewalk gratings, subwaygratings, engine room walks and the like, or adapted for use under heavyroad traiic, as on highway bridges, ramps, freight platforms, or thelike.

According to this invention an improved grating is constructed fromintersecting sets of bars, one or both of which comprise angle barsections set vertically with the tianges of the angles being squeezedtogether at the areas of intersection with the bars of the other set,thereby providing a succession of pockets or cells of V-shaped sectionwidest at the middle and tapering in width but increasing in depthtowards their ends. These pockets are then filled with a pavingcomposition until the top of the grating is substantially at and level.Thus at the points of intersection the metal may be exposed, whilebetween the areas oi intersection the composition extends above themetal but is most eifectively retained in the grat? ing. rthis is anespecially desirable condition on highways where it reduces the tendencyof the wheels to track or sldd on the met-al and provides a successionof relatively wide composition areas and smaller metal areas on whichthe wheels roll while the open cells through the grating arecorresponding smaller, giving improved riding qualities. For other usesthe grating also provides a desirable surface, providing good footing.Incidentally the construction provides a grating of pleasing andattractive appearance. The grating may be used merely as such, oradvantageously integrated with bearer bars or load carrying members forheavy traffic conditions.

2,960,918 Patented Nov. 22, 1960 Other objects and advantages willappear when taken in connection with the accompanying drawings, wherein:

Fig. 1 is a plan view of a portion of a grating embodying the invention;

Fig. 2 is a transverse section in the plane of line II-II of Fig. l;

Fig. 3 is a longitudinal section of the same grating in the plane ofline III- III of Fig. 1 showing how the main bearer bars are secured tothe main supporting beams and the cross bars at the points ofintersection of the bars;

Fig. 4 is a portion of a transverse section in the plane of line IV-IVof Fig. 1; and

Fig. 5 is a portion of a longitudinal section in the plane of line V-Vof Fig. l.

Referring to the drawings in detail, there is shown a composite grating1 comprised of one set of bars 2 which are intersected by cross bars 3,the whole grating being supported upon and integrated with mainload-carrying or bearer bars 4.

Each of the grating bars 2 and 3 is formed from an angle bar section,the flanges 6 of which are squeezed together at regular short intervalsS, thereby forming a succession of cells or pockets 7 of V-shapedsection with the squeezed portions connecting the pockets. The bars thusformed are joined together in intersecting relation with theintermediate edges 5 of the angles turned downwardly and the pockets 7opening upwardly. The squeezed portions 8 are at the points ofintersection. The bars may be pressure welded at the intersections, thatis, the bars of one set are initially located above the others and theyare then subjected to pressure while electric current at the areas ofcontact causes such heating of the metal that the two bars will beforced together and welded and the tops of the bars at the intersectionare brought to substantially a common level. Instead of beingpressurewelded, the flattened intersecting portions of the bars may benotched to intert in the conventional egg crate manner and then welded,out after assembly the tops of both sets of bars at the intersectionsare flush. The squeezing of the sections in this manner at relativelyclose intervals causes the edges of the pockets to curve laterally ofthe longitudinal axis of the sections, with the pockets being widest atthe middle. At the same time, the squeezing of the iianges togetherincreases the depth of the sections at the points of intersection andthe edges of the pockets are therefore concaved in vertical contour, asshown in Fig. 2, so that viewed from the side, the edges of the barappear to be inwardly scalloped.

The grating thus constructed may be used in this form, but for heavytrathc, it may be set on spaced parallel bearer or load-carrying bars 4,here shown as I-beam sections, these bars being positioned underalternate angle bars 2, the intermediate edges 5 of the angle barssetting on the tops of the heads i7 of the bearer bars. 19 designatesthe lower cross bars or lower load-distributing bars joining the bottoms18 of the bearer bars at intervals. The grating may then be welded tothe bearer bars by welds 11 (see Figs. 3 and 4) which also may extendingup the outside of the grating at the corner formed by the intersectinggrating bars as indicated at 12, the weld being preferably extended tothe top of the grating at 13. When thus welded to the bearer bars, thegrating bars 2 become integrated with the bearer bars, increasing theirdepth and hence their load-carrying capacity, while the cross bars 3distribute the load.

Gratings as thus formed are made up in panels, and after the grating hasbeen assembled, the pockets 7 are filled with a tough, wear andimpact-resistant resin-aggregate anti-skid composition, the pocketsbeing lled to the level of the highest parts of the grating, i.e., the

areas of intersection, and therefore extend above the level of the sideedges of the pockets. The composition is one having a high degree ofadhesion to the metal. The two sloping sides of the pockets provideextensive surface to which the material can adhere, while the mass ofcomposition diminishes in the lower part of the grating, thus Vmaking amost economical use of the comosition which is relatively expensive. Atthe same time the ilat top areas of the composition provide relativelylarge tread surfaces. The Scaphoid or boat shape of the pockets is onewhich also aids in effectively retaining the composition in the grating.

The resin-abrasive composition, which per se is no part of the presentinvention, may be of any of the various compounds described in myapplication Serial No. 456,380,1iled September 16V, 1954, of which thepresent application is *an improvement, or disclosed in the applicationof Harry S. Nagin and Donald H. Russell, Serial No. 427,873, iiled May5, 1954, in both of which the resin is comprised in substantial part orentirely of an epoxy resin and the abrasive is a particulate or granularmaterial such as grains of aluminum oxide or other abrasive, sand, or anabrasive in conjunction with sand. Epoxy resins, when cured with asuitable catalyst, may be cured in situ at room temperature. They adheretenaciously to the metal over all temperature conditions to which agrating is normally subjected in use, neither becoming excessivelybrittle when very cold, nor softening when exposed to hot sunshine. Theyare the reaction products of epichlorohydrin and diphenylolpropane, andare available as liquids, semi-liquids, and solids. In the practice ofthe present invention I prefer to use an epoxy resin having a lightsyrupy consistency at room temperature. Commercially suitable resinshaving suitable viscosities for my purpose are typified by twopreparations available under the trade name Epon as No. Vi and No. 828.These resins are more fully described in a printed technical bulletinSC58-92 published by Shell Chemical Corporation in 1958 as to theirviscosities and epoxide equivalents. These are typical and not exclusiveexamples. To cure these resins, it is necessary to use a catalyst suchas a polyamine which is introduced at the time that the resin abrasivecomposition is prepared and remains therein. I have found diethylenetriamine to be satisfactory in the ratio of about by Weight of catalystto resin. The abrasive aggregate is preferably coarse granular aluminumoxide.

While the material aboved described is especially desirable for severetraffic conditions, I may use any other suitable filling, as for exampleasphalt Vwith or without abrasive particles therein, Portland cementwith or without abrasive aggregate, or even preformed molded blocks orinserts secured in the angles by an adhesive, such as an epoxy resin orother adhesive material or by other securing means.

When the grating formed of the intersecting angle bars formed in themanner ldescribed is secured to the bearer bars, the cross angle barsform load-distributing bars, and as explained above, the longitudinalangles give increased depth to the bearer bars, increasing theirloadcarrying capacity. Y

As indicated above, while I have shown a specic form of grating, thisshould be considered as illustrative only and various modifications andchanges may be made in the grating within the contemplation of myinvention and under the scope of the yappended claims.

I claim:

l. A composite grating comprised of two sets of intersecting bars, thebars of at least one of the two sets having two side walls that areconnected at their bottom edges, the side walls being bowed outwardly inthe plane of the grating between their points of intersection with thebars of the other set to form upwardly-opening pockets withdownwardly-converging sides between the points of intersection, thepockets being joined by narrow connecting portions having the two sidewalls parallel, said bars of the other set having two parallel sidewalls at the intersection, said bars intersecting at said narrowconnection portions with the bars of the other set, the bars beingwelded to eachV other,` at the intersections, the bars of both (setshaving theirupper edges in the same plane at the intersections.

2. A composite grating comprised of two sets of like intersecting bars,the bars of each set having two side walls that are connected at theirbottom edges, the side walls being bowed outwardly in the plane of thegrating between their points of intersection with the bars of the otherset to form upwardly-opening pockets with downwardly-converging sides,the pockets being joined by narrow connecting portions having the twosides walls parallel, the said connecting portions of the two sets ofbars being located at the intersections of the bars, the bars beingwelded to each other at the intersections with the bars of both setshaving their upper edges in the same plane at the intersections.

3. A composite grating as defined in claim 2 wherein the edges of theV-shaped pockets are concaved, and a tread material filling the pocketsand extending above the concaved edges to the level of the top of thegrating at the intersection. Y Y

4. A composite grating as defined in claim 3 in which the treadlmaterial is a resin-abrasive mix which adheres rmly to the metal.

5. A composite grating as defined in claim 3 in which the tread materialcomprises a mixture of abrasive grains and an epoxy resin, the mixturehaving a high impact resistance and strong adhesion to the metal.

6. A composite grating as defined in claim 3 in which load-bearing barsare welded along the bottom edges of at least some of the bars of oneset and are coextensive therewith.

References Cited in the tile of this patent p UNITED STATES VPATENTS865,180 Horner Sept. 3, 1907 1,603,678 Furey Oct. 19, 1926 1,665,846Denni Apr. 10, 1928 1,784,895 Dunker Dec. 16, 1930 2,246,898 Sayre June24, 1941 FOREIGN PATENTS 519,055 France 1921 851,219 France 1939 811,033Germany Aug. 16, 1951

